Shelf



FIG. 1 is a top, right, front perspective view of a shelf showing our new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken line showing is for the purpose of illustrating unclaimed portions of the article and forms no part of the claimed design. 

CLAIM The ornamental design for a shelf, as shown and described. 